Remote Direct Memory Access Transport for Remote Procedure Call
RFC 5666

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Internet Engineering Task Force (IETF)                         T. Talpey
Request for Comments: 5666                                  Unaffiliated
Category: Standards Track                                   B. Callaghan
ISSN: 2070-1721                                                    Apple
                                                            January 2010

    Remote Direct Memory Access Transport for Remote Procedure Call

Abstract

   This document describes a protocol providing Remote Direct Memory
   Access (RDMA) as a new transport for Remote Procedure Call (RPC).
   The RDMA transport binding conveys the benefits of efficient, bulk-
   data transport over high-speed networks, while providing for minimal
   change to RPC applications and with no required revision of the
   application RPC protocol, or the RPC protocol itself.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc5666.

Copyright Notice

   Copyright (c) 2010 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
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   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Talpey & Callaghan           Standards Track                    [Page 1]
RFC 5666                 RDMA Transport for RPC             January 2010

   This document may contain material from IETF Documents or IETF
   Contributions published or made publicly available before November
   10, 2008.  The person(s) controlling the copyright in some of this
   material may not have granted the IETF Trust the right to allow
   modifications of such material outside the IETF Standards Process.
   Without obtaining an adequate license from the person(s) controlling
   the copyright in such materials, this document may not be modified
   outside the IETF Standards Process, and derivative works of it may
   not be created outside the IETF Standards Process, except to format
   it for publication as an RFC or to translate it into languages other
   than English.

Table of Contents

   1. Introduction ....................................................3
      1.1. Requirements Language ......................................4
   2. Abstract RDMA Requirements ......................................4
   3. Protocol Outline ................................................5
      3.1. Short Messages .............................................6
      3.2. Data Chunks ................................................6
      3.3. Flow Control ...............................................7
      3.4. XDR Encoding with Chunks ...................................8
      3.5. XDR Decoding with Read Chunks .............................11
      3.6. XDR Decoding with Write Chunks ............................12
      3.7. XDR Roundup and Chunks ....................................13
      3.8. RPC Call and Reply ........................................14
      3.9. Padding ...................................................17
   4. RPC RDMA Message Layout ........................................18
      4.1. RPC-over-RDMA Header ......................................18
      4.2. RPC-over-RDMA Header Errors ...............................20
      4.3. XDR Language Description ..................................20
   5. Long Messages ..................................................22
      5.1. Message as an RDMA Read Chunk .............................23
      5.2. RDMA Write of Long Replies (Reply Chunks) .................24
   6. Connection Configuration Protocol ..............................25
      6.1. Initial Connection State ..................................26
      6.2. Protocol Description ......................................26
   7. Memory Registration Overhead ...................................28
   8. Errors and Error Recovery ......................................28
   9. Node Addressing ................................................28
   10. RPC Binding ...................................................29
   11. Security Considerations .......................................30